Method op cleaning garments



1'. M. LANGAIS:

METHOD oF CLEANING Filed Nov.. 1, V193'? Er A.. 2,174,793

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METHD @F @EEANENG GRFEEN'ES Thomas M. Langen and Guy E. Condit, St.lLonfis, Mo., assignors to Riverside Manuiacturing Company, St. souriLouis, litio., acompany of Mis@ l Application November li, 1937, Sei-iaiNo. l2,97

5 Claims.

p given quantity of clothes cleaned, and thereby i eii'ect greateconomies in the cleaning materials used and increasing the emciency ofthe clothes cleaning operations. The manner of accomplishingthis object,together with the other advantages inherent in our improved method, willbe l better appreciated from a brief description of the processes nowemployed in the dry cleaning industry.

It was formerly common practice in the dry cleaning industry to use aminimum amount of 20 soap in the cleaning solution and to discard thesoap bath after each load of garments cleaned. A few years ago many ofthe dry cleaners adopted the practice of using a strong soap solution(now. generally referred to in the industry as S. S. S.) in which therewas 3% to 10% of soap by volume, and which solution was used on morethan one run of garments. The strong soap so lution method is veryeffective in thel removal oi both spots and stains and ordinaryinsoluble soil. but it is diilicult to maintain an eiiiclent andsatisfactory condition because of the acid condition of the soil withinthe garments.

Most dry cleaning soaps, and particularly those suitable for use in astrong soap solution method of cleaning, are super-fatted; that is,there is an excess of fatty acid beyondthat necessary to effect completeneutralization of the alkaliin the soap (this excess of fatty acid isconsidered desirable because it facilitates solution or dispersion ofthe soap in the dry cleaning solvent, whereas completely saponiiiedsoaps usually require an auxiliaryuagent, such as an alcohol, to effectproper dispersion or solution in the solvent). Then too, the acidcontent of the bath 45 is increased by the garment soil which is almostalways of an acid nature since it consists principally of inertmaterial, perspiration, body oils,

and sulfur gases from the atmosphereespecially in the case of garmentsWorn in the city. This 5.0 acid soil breaks down the soap andafter a fewloads of garments have been cleaned, the eiliciency of the soap bathdrops ofi rapidly, giving poorer and poorer cleaning results as eachsuc-` ceeding load of garments is cleaned. Therefore, I in rst class.cleaning plants, it has become the (Cl. anida l custom to discardthesoap bath after relatively few loads of garments have been cleaned init. The losses introduced by this uneconomical practice have beensomewhat reduced byv attempts to maintain the soap solution at. therequired strength by the addition of small quantities of fresh soap tothe bath with each load ci' garments cleaned. However, this practice isnot entirely satisfactory, as will be p ointed out later.

It is a matter of common knowledge in the clothes cleaning industry thatthe acid soil in the l garments breaks down the soap, and a patent hasbeen granted to Ralph A. Morgen, No. 1,979,399, disclosing the use indry cleaning of an alkaline soap solution (called a detergent `by thepatentee) which soap solution or detergent contains sumcient free alkalito neutralize the acidity transferred to the solventl from the garmentsbeing cleaned. However/this process is applicable only inthe cleaning ofa single batch of garments, as the coap is immediately removed from thedry cleaning solvent after the cleaning operation by means of aclarifying powder. The real action of the acid soil on a strong soap4solution does not seem to be clearly understood inthe art.

We have found, after several years of study and experimentation, thatthe principal action of the soil on the soap is the removal of thealkali from the soap and th'e decrease of the degree of neutralizationof the soap below its original condition. This decrease in the degreeAof neutralization (which is `the equivalent of increasing thesuper-fattiug) has a very marked effect on the cleaning qualities of adry cleaning soap bath. Particularly is this true when the percentage ofneutralization drops below a more or less critical point,y which varieswith the type of soap being used.. As the neutralization falls belowthis critical point, the etiiciency of the strong soap solutiondecreases rapidly.

Therefore, when a succession of clothes batches are cleaned with thesame dry cleaning soap bath, the addition of small amounts of 70%neutralized dry cleaning soap will but slightly increase the percentageof neutralization of a bath containing a large amount of `soap which hasdropped to 40% neutralization. 1

We have discovered that if, instead of attempting to maintain theeffective soap content of the bath by the addition of small amounts ofsoap with each. bath of clothes cleaned, an alkali is added directly tothe bath to compensate for the increase in the acid content of the bah,the cleaning eiilciency of the bath will be maintained veryconsiderably. Of course, the quantity of this al- When this has beenaccomplished, the valves are manipulated so as to cause the soapsolution to circulate through the washer and the balance of the system.

However, if a weak alkali, such as ammonia, is used in the intermittentprocess, it is not necessary to agitate the alkali separately.

When the practise of continuously adding the alkali is followed, thevalves may be regulated so as to allow the alkali to circulate with thesoap solution through the clothes cleaning circuit without the necessityof independent agitation of the alkali with the cleaning uid.

Having described our invention, we claim:

1. In the process of dry cleaning 'acid soiled garments includingapplication to the soiled garments, or other articles to be cleaned, ofa nonaqueous solvent and a soap, the step of reconditioning the usedsoap solution by adding thereto an alkali in suilicient quantity tocompensate for the addition to the soap solution of the acid soilextracted from the garments. l

2. In the process of dry cleaning acid soiled garments includingapplication to the soiled garments, or other articles to be cleaned, ofa nonaqueous solvent anda soap, the step of reconditioning the used soapsolution by continuously adding thereto during the cleaning operation analkali in suillclent quantity to compensate for the addition to the soapsolution of the acid soil extracted from the garments. 3. In the processof dry cleaning acid soiled garments including application to the soiledgarments, or other articles to lbe cleaned, of a nonaqueous solvent anda soap, the step of reconditioning the used soap solution byperiodically adding an alkali in suicient quantity to compensate for theaddition to the soap solution of the acid soil extracted from thegarments.

4. In the piacess of dry cleaning acid soiled garments includingapplication to the soiledgar` ments, or lother articles to be cleaned,of a nonaqueous solvent and a soap, the step of reconditioning the usedsoap solution by periodically adding an alkali in suiiicient quantity tocompensate for the addition to the soap solution of the acid soilextracted from the garments, and agitatingsaid alkali with the soapsolution while temporarilyldiscontinuing the application of the soapsolution to the garments. f

5. In the process of dry cleaning acid soiled garments, includingapplication to the soiled garments, or other articles to be cleaned, ofa nonaqueous solvent and a soap in a suiiicient quantity to produce inexcess of a 1% soap solution, the step of adding an alkali in suicientquantity to neutralize the acid introduced into the soap by the soilfrom the garments'.

THOMAS M. LANGAN.

GUY H. CONDIT.

' Get. 3, w39.

- R. L. LAY

, MOISTURE TRAP FOR DRY PIPES Filed Jan.l 1l, 1938 INVENTOR. Roy L. LAy.

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